262 Researchels respecting the Action of Benxoates,^c. 



proportion of dried oxide of iron in the first experiment (o), 

 and also with that of calcintd oxide; this product iieing 

 a hydiat, which its appearance indicated. It was not red- 

 brown but pure brown externally, looking black within, 

 and baked together in hard pieces. 



IV. Attempt to separate Iron with Benzoate of Am'monia. 



a. 0'20 of agnimme of red oxide of iron was dissolved in 

 muriatic acid, and mixed with a solution of pure alumina 

 in sulphuric acid, where the weight of the alumina was 

 several times greater than that of the oxide of iron. The 

 mixed solution was neutralized with caustic ammonia, di- 

 luted with water, and benzoate of ammonia added until a 

 portion taken therejrom did not with tincture of galls dis- 

 cover any iron therein. The fluid was agitated now and 

 then, and after the space of some hours was filtered. It 

 did not contain any sensible traces of iron. The benzoate 

 of iron was well washed with cf)ld water, dried, and after a 

 Strong calcination left the O-aO of a gramme of oxide of iron 

 employed. 



I. 0'3.i aram. of red oxide of iron was mixed with O'lO 

 of a cramine of oxide oinickel, previously purified, tree from 

 iron and dark gray, dnd the mixture was dissolved in mu- 

 riatic acid. The sdlution was diluted with water, accurately 

 jaeuiralized with ammonia, and precipitated with benzoate 

 of ammonia. The precipitate was well washed, and left 

 after a strong calcination |)recise!y 0'33 of a gramme of red 

 oxide of iron. The iron was consequently to the utmost 

 nicety precipitated, and separated from the nickel. 



c. A similar experiment \vith pure cobalt and oxide of 

 iron had the like result. 



d. 0' 10 of a gramme of red oxide of iron and ()• 15 gram, of 

 calcined pure oxide of mnrj^anese were dissolved in di- 

 luted muriatic acid. The surplus of acid was saturated 

 with caustic ammonia. Benzoate of ammonia was adde4 

 ijntil all precipitation ceased ; this was taken on the filter, 

 >vhich was correctly weighed, was washed well with cold 

 wafer, dried, and calcmed stronojly. The residue was a pure 

 dark red oxide of iron weighing 0*39 of a gramme. The de- 

 ficient O'Ol of a gramme was contained in what had stuck to 

 the filter and the crucible. The oxide did pot indicate any 

 contamination of manganese. 



e. 0'80 of a gramme black oxide of mn^seoriese and O'lO 

 of a granune of oxide of iron were dissolved in muriatic acid. 

 The solution, diluted with water, was neutralized until a 

 poinniencement of turbidity^ with caustic ammonia and the 



oxide 



